Our body consists of water and a large number of complicated chemicals which are, together assembled in cells. These cells are the building blocks of our body. Each cell is self contained and has a specific function in the body.
Our body has more than 50,000 billion cells and the shape of a cell depends on what type of job it has to do.
Nerve cells are long and look like thread which can carry messages around the body. Red blood cells are very tiny. White blood cells are shapeless so, that they can squeeze between other cells and attack the invaders, such as bacteria. Other cells, control the production of proteins, essential for our development and growth.
Below Cells info from Wikipedia (Read More):-
The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life.[1] Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an unfertilized ostrich egg cell.
http://en.wikipedia.org/wiki/Cell_%28biology%29
